Optimal radiation therapy for cancer in most instances requires multislice CT or MR studies of the cancer and adjacent structures for the preparation of sophisticated, computerized three- dimensional treatment plans. The cost of these technologically advanced computers and software to perform state-of-the-art radiation therapy treatment planning is high. For many radiation therapy departments the cost is too great to permit access to the current technology. The aim of this project is to develop a low cost, relatively high speed image telecommunication system that will make it feasible for radiation therapy departments to transmit CT and/or MR images to a centralized regional radiation therapy treatment planning center for the computerized preparation of treatment plans. A telecommunication system based on microcomputer processors with local hard disk storage, high resolution (1024 X 1024 X 12 bit monitors) and 9600 Baud modems is proposed. The study seeks to test telecommunication and processing speed, and the accuracy of data transmission.